From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qv1-xf44.google.com (mail-qv1-xf44.google.com [IPv6:2607:f8b0:4864:20::f44]) by sourceware.org (Postfix) with ESMTPS id E7FA6388A40A for ; Wed, 25 Nov 2020 15:40:49 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E7FA6388A40A Received: by mail-qv1-xf44.google.com with SMTP id 62so1101133qva.11 for ; Wed, 25 Nov 2020 07:40:49 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=gy5Ux+GVav7jritddHbDuZYBUNZn48Rzxv74wJ5XHiE=; b=pEbKtM491aDPXSv/hXsi3/lGI5HY7mOfKcthvTxw6ZRCyFcMbXPwenNmsMCXAu6clO Vnz3XW/N0kkIH5Ib/v1M8N0N/87mFMADFoW1HTvZFUD4/jyCrPRZSlz4KfmpT6FP0j36 Ctz9zu+GcTCZVcow2IX3PmV+t+Wwvpd0n9r90xBdGp1VEznkBNys4HkfMtsbaHdRx3TH XuCxQQ+jdCuijBWJ5IYBVlc+fkHr/SxNjftrA2szP28kyI3HBDp6r8vXtr0rUxrLZPMg o6Qa9EuGJPvyuO3imsg+9aZvL7gmuvDJOIu4sxmdeV4fxNNEccLhqap8jcIYTxaHeHal Fhyw== X-Gm-Message-State: AOAM531zmp4Yp4cXaJev/AEUrgso+X0PcBh7lcDpcvrS9MahzXGk1dWS bRIpEGx7oqjKznq6OetSdPGFX2qdH3w9IQ== X-Google-Smtp-Source: ABdhPJz5gdzS9ILg2rUNP28bvpPIPbp64VsPUA903SbgJwuPrvufO3srugFmV3qRS8FzPM4QSBxXAg== X-Received: by 2002:ad4:548b:: with SMTP id q11mr4179961qvy.44.1606318849098; Wed, 25 Nov 2020 07:40:49 -0800 (PST) Received: from [192.168.1.4] ([177.194.48.209]) by smtp.googlemail.com with ESMTPSA id w9sm298862qti.45.2020.11.25.07.40.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 25 Nov 2020 07:40:48 -0800 (PST) Subject: Re: [PATCH 09/13] linux: nptl: Replace lll_futex_{timed_}wait by futex-internal.h To: Mike Crowe Cc: libc-alpha@sourceware.org, Michael Kerrisk References: <20201123195256.3336217-1-adhemerval.zanella@linaro.org> <20201123195256.3336217-9-adhemerval.zanella@linaro.org> <20201125153231.GA1391@mcrowe.com> From: Adhemerval Zanella Autocrypt: addr=adhemerval.zanella@linaro.org; prefer-encrypt=mutual; keydata= mQINBFcVGkoBEADiQU2x/cBBmAVf5C2d1xgz6zCnlCefbqaflUBw4hB/bEME40QsrVzWZ5Nq 8kxkEczZzAOKkkvv4pRVLlLn/zDtFXhlcvQRJ3yFMGqzBjofucOrmdYkOGo0uCaoJKPT186L NWp53SACXguFJpnw4ODI64ziInzXQs/rUJqrFoVIlrPDmNv/LUv1OVPKz20ETjgfpg8MNwG6 iMizMefCl+RbtXbIEZ3TE/IaDT/jcOirjv96lBKrc/pAL0h/O71Kwbbp43fimW80GhjiaN2y WGByepnkAVP7FyNarhdDpJhoDmUk9yfwNuIuESaCQtfd3vgKKuo6grcKZ8bHy7IXX1XJj2X/ BgRVhVgMHAnDPFIkXtP+SiarkUaLjGzCz7XkUn4XAGDskBNfbizFqYUQCaL2FdbW3DeZqNIa nSzKAZK7Dm9+0VVSRZXP89w71Y7JUV56xL/PlOE+YKKFdEw+gQjQi0e+DZILAtFjJLoCrkEX w4LluMhYX/X8XP6/C3xW0yOZhvHYyn72sV4yJ1uyc/qz3OY32CRy+bwPzAMAkhdwcORA3JPb kPTlimhQqVgvca8m+MQ/JFZ6D+K7QPyvEv7bQ7M+IzFmTkOCwCJ3xqOD6GjX3aphk8Sr0dq3 4Awlf5xFDAG8dn8Uuutb7naGBd/fEv6t8dfkNyzj6yvc4jpVxwARAQABtElBZGhlbWVydmFs IFphbmVsbGEgTmV0dG8gKExpbmFybyBWUE4gS2V5KSA8YWRoZW1lcnZhbC56YW5lbGxhQGxp bmFyby5vcmc+iQI3BBMBCAAhBQJXFRpKAhsDBQsJCAcDBRUKCQgLBRYCAwEAAh4BAheAAAoJ EKqx7BSnlIjv0e8P/1YOYoNkvJ+AJcNUaM5a2SA9oAKjSJ/M/EN4Id5Ow41ZJS4lUA0apSXW NjQg3VeVc2RiHab2LIB4MxdJhaWTuzfLkYnBeoy4u6njYcaoSwf3g9dSsvsl3mhtuzm6aXFH /Qsauav77enJh99tI4T+58rp0EuLhDsQbnBic/ukYNv7sQV8dy9KxA54yLnYUFqH6pfH8Lly sTVAMyi5Fg5O5/hVV+Z0Kpr+ZocC1YFJkTsNLAW5EIYSP9ftniqaVsim7MNmodv/zqK0IyDB GLLH1kjhvb5+6ySGlWbMTomt/or/uvMgulz0bRS+LUyOmlfXDdT+t38VPKBBVwFMarNuREU2 69M3a3jdTfScboDd2ck1u7l+QbaGoHZQ8ZNUrzgObltjohiIsazqkgYDQzXIMrD9H19E+8fw kCNUlXxjEgH/Kg8DlpoYJXSJCX0fjMWfXywL6ZXc2xyG/hbl5hvsLNmqDpLpc1CfKcA0BkK+ k8R57fr91mTCppSwwKJYO9T+8J+o4ho/CJnK/jBy1pWKMYJPvvrpdBCWq3MfzVpXYdahRKHI ypk8m4QlRlbOXWJ3TDd/SKNfSSrWgwRSg7XCjSlR7PNzNFXTULLB34sZhjrN6Q8NQZsZnMNs TX8nlGOVrKolnQPjKCLwCyu8PhllU8OwbSMKskcD1PSkG6h3r0AquQINBFcVGkoBEACgAdbR Ck+fsfOVwT8zowMiL3l9a2DP3Eeak23ifdZG+8Avb/SImpv0UMSbRfnw/N81IWwlbjkjbGTu oT37iZHLRwYUFmA8fZX0wNDNKQUUTjN6XalJmvhdz9l71H3WnE0wneEM5ahu5V1L1utUWTyh VUwzX1lwJeV3vyrNgI1kYOaeuNVvq7npNR6t6XxEpqPsNc6O77I12XELic2+36YibyqlTJIQ V1SZEbIy26AbC2zH9WqaKyGyQnr/IPbTJ2Lv0dM3RaXoVf+CeK7gB2B+w1hZummD21c1Laua +VIMPCUQ+EM8W9EtX+0iJXxI+wsztLT6vltQcm+5Q7tY+HFUucizJkAOAz98YFucwKefbkTp eKvCfCwiM1bGatZEFFKIlvJ2QNMQNiUrqJBlW9nZp/k7pbG3oStOjvawD9ZbP9e0fnlWJIsj 6c7pX354Yi7kxIk/6gREidHLLqEb/otuwt1aoMPg97iUgDV5mlNef77lWE8vxmlY0FBWIXuZ yv0XYxf1WF6dRizwFFbxvUZzIJp3spAao7jLsQj1DbD2s5+S1BW09A0mI/1DjB6EhNN+4bDB SJCOv/ReK3tFJXuj/HbyDrOdoMt8aIFbe7YFLEExHpSk+HgN05Lg5TyTro8oW7TSMTk+8a5M kzaH4UGXTTBDP/g5cfL3RFPl79ubXwARAQABiQIfBBgBCAAJBQJXFRpKAhsMAAoJEKqx7BSn lIjvI/8P/jg0jl4Tbvg3B5kT6PxJOXHYu9OoyaHLcay6Cd+ZrOd1VQQCbOcgLFbf4Yr+rE9l mYsY67AUgq2QKmVVbn9pjvGsEaz8UmfDnz5epUhDxC6yRRvY4hreMXZhPZ1pbMa6A0a/WOSt AgFj5V6Z4dXGTM/lNManr0HjXxbUYv2WfbNt3/07Db9T+GZkpUotC6iknsTA4rJi6u2ls0W9 1UIvW4o01vb4nZRCj4rni0g6eWoQCGoVDk/xFfy7ZliR5B+3Z3EWRJcQskip/QAHjbLa3pml xAZ484fVxgeESOoaeC9TiBIp0NfH8akWOI0HpBCiBD5xaCTvR7ujUWMvhsX2n881r/hNlR9g fcE6q00qHSPAEgGr1bnFv74/1vbKtjeXLCcRKk3Ulw0bY1OoDxWQr86T2fZGJ/HIZuVVBf3+ gaYJF92GXFynHnea14nFFuFgOni0Mi1zDxYH/8yGGBXvo14KWd8JOW0NJPaCDFJkdS5hu0VY 7vJwKcyHJGxsCLU+Et0mryX8qZwqibJIzu7kUJQdQDljbRPDFd/xmGUFCQiQAncSilYOcxNU EMVCXPAQTteqkvA+gNqSaK1NM9tY0eQ4iJpo+aoX8HAcn4sZzt2pfUB9vQMTBJ2d4+m/qO6+ cFTAceXmIoFsN8+gFN3i8Is3u12u8xGudcBPvpoy4OoG Message-ID: Date: Wed, 25 Nov 2020 12:40:46 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201125153231.GA1391@mcrowe.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-14.0 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 25 Nov 2020 15:40:51 -0000 On 25/11/2020 12:32, Mike Crowe wrote: > On Monday 23 November 2020 at 16:52:52 -0300, Adhemerval Zanella wrote: >> The idea is to make NPTL implementation to use on the functions >> provided by futex-internal.h. >> >> Checked on x86_64-linux-gnu and i686-linux-gnu. >> --- >> nptl/lowlevellock.c | 6 +++--- >> nptl/pthread_mutex_lock.c | 9 +++++---- >> nptl/pthread_mutex_setprioceiling.c | 5 +++-- >> nptl/pthread_mutex_timedlock.c | 6 +++--- >> 4 files changed, 14 insertions(+), 12 deletions(-) > > [snip] > >> diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c >> index e643eab258..343acf6107 100644 >> --- a/nptl/pthread_mutex_timedlock.c >> +++ b/nptl/pthread_mutex_timedlock.c >> @@ -561,9 +561,9 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex, >> goto failpp; >> } >> >> - lll_futex_timed_wait (&mutex->__data.__lock, >> - ceilval | 2, &rt, >> - PTHREAD_MUTEX_PSHARED (mutex)); >> + __futex_abstimed_wait64 ( >> + (unsigned int *) &mutex->__data.__lock, clockid, >> + ceilval | 2, &rt, PTHREAD_MUTEX_PSHARED (mutex)); > > I think you've replaced the lll_futex_timed_wait call that expects a > relative timeout with a __futex_abstimed_wait64 call that expects an > absolute timeout, yet you still appear to be passing the relative timeout. > > However, it turns out that the implementation for the > PTHREAD_MUTEX_PP_RECURSIVE_NP and friends case appears to be have been > completely broken with clockid != CLOCK_REALTIME ever since I added it in > 9d20e22e46d891b929a72b0f35586e079eb083fd anyway since the relative timeout > is calculated by calling __clock_gettime64(CLOCK_REALTIME) (although at the > time this was a less obvious __gettimeofday call.) > > I'll work on writing some test cases for the those types of mutex in the > hope of catching both flaws before fixing them. Indeed, there is no need to calculate the relative timeout anymore. I think the fix below should pass the absolute timeout directly. I will check a possible regression tests as well. diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c index aaaafa21ce..86c5f4446e 100644 --- a/nptl/pthread_mutex_timedlock.c +++ b/nptl/pthread_mutex_timedlock.c @@ -508,7 +508,6 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex, if (__pthread_current_priority () > ceiling) { result = EINVAL; - failpp: if (oldprio != -1) __pthread_tpp_change_priority (oldprio, -1); return result; @@ -540,37 +539,9 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex, if (oldval != ceilval) { - /* Reject invalid timeouts. */ - if (! valid_nanoseconds (abstime->tv_nsec)) - { - result = EINVAL; - goto failpp; - } - - struct __timespec64 rt; - - /* Get the current time. */ - __clock_gettime64 (CLOCK_REALTIME, &rt); - - /* Compute relative timeout. */ - rt.tv_sec = abstime->tv_sec - rt.tv_sec; - rt.tv_nsec = abstime->tv_nsec - rt.tv_nsec; - if (rt.tv_nsec < 0) - { - rt.tv_nsec += 1000000000; - --rt.tv_sec; - } - - /* Already timed out? */ - if (rt.tv_sec < 0) - { - result = ETIMEDOUT; - goto failpp; - } - __futex_abstimed_wait64 ( (unsigned int *) &mutex->__data.__lock, clockid, - ceilval | 2, &rt, PTHREAD_MUTEX_PSHARED (mutex)); + ceilval | 2, abstime, PTHREAD_MUTEX_PSHARED (mutex)); } } while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,